Area Forecast Discussion
Issued by NWS North Platte, NE

Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

000
FXUS63 KLBF 020843
AFDLBF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTH PLATTE NE
343 AM CDT THU OCT 2 2014

.SYNOPSIS...
ISSUED AT 343 AM CDT THU OCT 2 2014

H5 ANALYSIS FROM EARLIER THIS EVENING HAD A TRIO OF
UPPER LEVEL DISTURBANCES ACROSS NRN ALBERTA...AND THE NORTHWEST
TERRITORIES OF CANADA. RIDGING EXTENDED FROM THE EASTERN GREAT LAKES
NNW INTO HUDSON BAY...WHILE A TROUGH OF LOW PRESSURE WAS LOCATED
OVER THE CENTRAL ROCKIES FROM CENTRAL WYOMING INTO WESTERN COLORADO.
CURRENT WV IMAGERY HAS THIS FEATURE NOW OVER EASTERN WYOMING SWD TO
THE FRONT RANGE OF COLORADO. EAST OF THIS FEATURE...A BROAD AREA OF
SHOWERS AND THUNDERSTORMS EXTENDED FROM NERN COLORADO INTO
SOUTHWESTERN...CENTRAL AND NORTH CENTRAL NEBRASKA. THIS ACTIVITY
CONTINUES TO MOVE SLOWLY TO THE NORTH NORTHEAST OVERNIGHT. AT THE
SURFACE...A COLD FRONT EXTENDED ACROSS EASTERN KANSAS INTO SERN
NEBRASKA WITH A SECONDARY FRONTAL BOUNDARY EXTENDING FROM NERN
NEBRASKA INTO NWRN KS. UNDER CLOUDY SKIES...TEMPERATURES AS OF 3 AM
CDT RANGED FROM 50 AT IMPERIAL...AINSWORTH AND VALENTINE...TO 53
AT ONEILL.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 343 AM CDT THU OCT 2 2014

OVER THE NEXT 24 HOURS...THE MAIN FORECAST CHALLENGES ARE
TEMPERATURES TODAY AND TONIGHT...TIMING OF A STRONG COLD FRONTAL
PASSAGE AND WINDS BEHIND THE FRONT...AS WELL AS THE THREAT FOR
POST FRONTAL PCPN TONIGHT. FOR TODAY...THE UPPER LEVEL TROUGH OF
LOW PRESSURE CURRENTLY OVER THE FRONT RANGES OF COLORADO AND
WYOMING...WILL LIFT EAST INTO CENTRAL NEBRASKA THIS MORNING. EAST
OF THIS FEATURE...FAVORABLE MID LEVEL LIFT...WILL ALLOW THE THREAT
FOR PCPN TO LINGER INTO MORNING HOURS IN THE EASTERN CWA. ONGOING
FCST HAS THIS CAPTURED FAIRLY WELL AND HAVE ONLY MADE MINOR
CHANGES TO THE PRECIP FCST. LATER THIS AFTERNOON...SUBSIDENCE ON
THE BACK SIDE OF THE EXITING UPPER LEVEL TROUGH...WILL ALLOW FOR
SOME LIMITED CLEARING. THIS WILL ALLOW TEMPS TO REBOUND BACK INTO
THE MID AND UPPER 60S FOR HIGHS TODAY. A POWERFUL COLD FRONT WILL
APPROACH THE NWRN CWA AROUND SUNSET THIS EVENING...AND IS EXPECTED
TO CLEAR THE FORECAST AREA BY MIDNIGHT. H85 TEMPERATURES WILL FALL
10 TO 15 DEGREES C WITH PASSAGE OF THIS FEATURE...SO NO DOUBT IT
WILL BE WINDY WITH THE FROPA THIS EVENING. COLD AIR ADVECTION WILL
CONTINUE WELL BEHIND THE FRONT INTO THE OVERNIGHT...WHICH SHOULD
KEEP LOW LEVEL WINDS FROM DECOUPLING OVERNIGHT. FOR OVERNIGHT
LOWS...GENERALLY FAVORED THE WARMER MET GUIDANCE...WHICH TAKES
INTO ACCOUNT THE HIGHER WINDS COMPARED TO THE COOLER MAV GUIDANCE.
EVEN WITH THE EXPECTED WINDS AND BOUNDARY LAYER MIXING...LOWS WILL
FLIRT WITH THE FREEZING MARK IN THE NORTHEASTERN PANHANDLE AND
WESTERN CHERRY COUNTY TOWARD FRIDAY MORNING. ATTM...DECIDED TO
FORGO ANY FROST HEADLINES ATTM GIVEN THE EXPECTED LOW LEVEL MIXING
AND THE SHORT DURATION OF NEAR FREEZING TEMPS. FWIW...THE MAIN
FREEZING EVENT IS EXPECTED FRIDAY NIGHT UNDERNEATH CANADIAN HIGH
PRESSURE AND LIGHT WINDS. AS FOR PCPN CHANCES TONIGHT...NOT
EXPECTING MUCH IN THE WAY OF PCPN ALONG THE FRONT AS IT WILL BE
PLOWING INTO A FAIRLY DRY AIRMASS. HOWEVER A DECENT THREAT FOR
PRECIPITATION EXISTS NORTH OF THE SURFACE FRONT THANKS TO STRONG
MID LEVEL FRONTOGENESIS AND VERY FAVORABLE JET DYNAMICS. THIS AREA
OF STRONG LIFT ORIGINATES IN THE NORTHWESTERN FORECAST AREA THIS
EVENING...AND SINKS SOUTH AND SOUTHEAST INTO CENTRAL...THEN
SOUTHERN PORTIONS OF THE FORECAST AREA OVERNIGHT. DECIDED TO LIMIT
POPS TO 30 TO 40 PERCENT THOUGH AS AVAILABLE MOISTURE BEHIND THE
SURFACE FRONT APPEARS LIMITED ATTM.

.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 343 AM CDT THU OCT 2 2014

FORECAST FOCUS FROM LATE THIS WEEK THROUGH THE MIDDLE OF NEXT WEEK
IS ON TEMPERATURES AND FROST/FREEZE POTENTIAL FRIDAY THROUGH
SATURDAY...AS WELL AS WINDS FRIDAY. REMAINDER OF THE FORECAST
PERIOD LOOKS TO HAVE FAIRLY BENIGN WEATHER.

MODELS ARE SHOWING GOOD AGREEMENT...ESPECIALLY IN THE LARGE SCALE
PATTERN THROUGH THE MIDDLE OF NEXT WEEK. THAT BEING SAID...THERE
ARE DIFFERENCES IN MORE SMALL SCALE FEATURES THAT HAVE SLIGHT
IMPACTS ON THE FORECAST. BUT AS A WHOLE...GENERALLY HIGH
CONFIDENCE LEVEL ON THIS FORECAST PACKAGE.

THE UPPER LEVEL SYSTEM NOW OVER WESTERN CANADA...SPECIFICALLY THE
SHORTWAVE FEATURE SEEN OVER BRITISH COLUMBIA...AS WELL AS THE
SHORTWAVES OVER THE WESTERN NORTHERN TERRITORIES AND EAST CENTRAL
ALBERTA WILL CONGEAL INTO A STRONG UPPER LEVEL TROUGH WHICH WILL
DIG SOUTHEAST INTO THE PLAINS AND INTO THE EASTERN HALF OF THE
CONUS THROUGH FRIDAY AND SATURDAY. THE AIR ASSOCIATED WITH THIS
SYSTEM IS ANOMALOUSLY COLD...AS STANDARDIZED ANOMALIES SHOW THE
CORE OF THE SYSTEM BEING 3-4 STANDARD DEVIATIONS BELOW NORMAL. THE
COLDEST AIR WILL SLIDE JUST TO THE EAST OF THE LOCAL AREA...BUT
WILL STILL LEAD TO BELOW NORMAL TEMPERATURES FOR A FEW DAYS.

THE PRIMARY COLD FRONT WILL PUSH THROUGH NEBRASKA THURSDAY NIGHT
WITH STRONG COLD AIR ADVECTION OCCURRING BEHIND THE FRONT THROUGH
THE MORNING AND EARLY AFTERNOON FRIDAY. WITH THE COLD AIR
SUPPORTING DOWNWARD MOTION...AND WITH SUBSIDENCE EXPECTED
THROUGH THE 1000-500MB LAYER SHOULD HAVE MOSTLY SUNNY SKIES...AND
WITH THAT WARMING EVEN WITH THE COLDER AIRMASS IN PLACE SHOULD GET
DECENT MIXING THROUGH FRIDAY AFTERNOON...TO AROUND 750MB. THIS MIXED
LAYER SHOULD PRODUCE SURFACE TEMPERATURES IN THE 50S TO POSSIBLY
LOW 60S IN FAR SOUTHWEST NEBRASKA. THERE ARE SOME MODELS SHOWING
HIGHS IN THE UPPER 40S OVER NORTH CENTRAL NEBRASKA...BUT WITH THE
SUNSHINE THAT SEEMS A BIT TOO COLD AT THIS TIME. ALSO...WITH THE
DEEP MIXING...WILL GET WINDS TO MIX THROUGH THIS LAYER WHICH
SHOULD LEAD TO A FAIRLY WINDY DAY FOR MUCH OF NEBRASKA. THE
STRONGEST WINDS LOOK TO BE OVER NORTH CENTRAL NEBRASKA...WHERE THE
PRESSURE GRADIENT WILL BE THE TIGHTEST. IN THESE AREAS...WOULDN/T
BE SURPRISED TO SEE SUSTAINED WINDS NEARING 30MPH AND GUSTS
TOWARDS 45 MPH.

FRIDAY NIGHT AND SATURDAY MORNING SHOULD BE THE COLDEST OF THE
SEASON SO FAR. HIGH PRESSURE BUILDS IN ACROSS THE PLAINS OVERNIGHT
SO WINDS WILL DIMINISH...MEANWHILE CLEAR SKIES WILL HELP THE
RADIATIONAL COOLING PROCESS PRODUCE A STRONG BOUNDARY LAYER
INVERSION. TEMPERATURES WILL HAVE WARMED SLIGHTLY BY 12Z SATURDAY
FROM THE COLDEST POINT ON FRIDAY. HOWEVER...STILL EXPECTING 850MB
TEMPERATURES RANGING FROM -3C TO 8C ACROSS THE FORECAST AREA
SATURDAY MORNING. EXPECTING A COLD MORNING...WITH THE FIRST
POTENTIAL FOR A HARD FREEZE ACROSS THE AREA FOR THE SEASON. THERE
IS SOME SPREAD FROM THE MODELS ON LOWS SATURDAY MORNING...BUT
GENERALLY WENT MORE ON THE COOLER SIDE OF THE GUIDANCE FOR TODAY/S
FORECAST. BUT STILL NOT THE COLDEST AS NAM AND GFS MOS OUTPUTS
STILL ABOUT 3-5 DEGREES COOLER THAN WHAT IS IN THE CURRENT
OUTGOING FORECAST. WITH THIS THREAT...FROST HAS BEEN CONTINUED IN
THE FORECAST FOR LATER FRIDAY NIGHT INTO SATURDAY MORNING.

FOR THE REMAINDER OF THE WEEKEND AND INTO NEXT WEEK THE UPPER LOW
WILL PULL NORTHWARD AND BECOME ANCHORED OVER ONTARIO. THIS WILL
KEEP THE DEEP TROUGH IN PLACE OVER THE EASTERN CONUS...WHILE
RIDGING BUILDS OVER THE WEST COAST. THIS PATTERN WILL KEEP THE
CENTRAL PLAINS UNDER NORTHWEST FLOW THROUGH TUESDAY. THERE DOES
LOOK TO BE MULTIPLE WEAK SHORTWAVE TROUGHS ROTATING AROUND THE
PRIMARY UPPER LOW WHICH WILL HAVE THE FOLLOWING IMPACTS ON THE
SENSIBLE WEATHER. AS EACH SHORTWAVE TROUGH PUSHES THROUGH THE
PLAINS...IT WILL BRING A REINFORCING SHOT OF COOLER AIR. ALTHOUGH
ANY TIME THIS OCCURS...IT WON/T BE A MAJOR TEMPERATURE SHIFT...BUT
INSTEAD WILL WILL PUSH ANY WARMER AIR THAT BUILDS NORTHWARD BACK
SOUTH AND KEEP TEMPERATURES A BIT COOLER THAN MAY HAVE BEEN
ANTICIPATED A FEW DAYS AGO. ALSO...ON SUNDAY THERE LOOKS TO BE
POTENTIAL FOR A QUICK SHOT OF RAIN AS A WEAK SHORTWAVE PUSHES
THROUGH THE AREA. CONFIDENCE ON THESE CHANCES THOUGH ARE LOW AS
THERE ISN/T ENOUGH CONSENSUS WITHIN THE MODELS TO HAVE A CLEAR
SIGNAL ON THE PRECIPITATION POTENTIAL. WILL BE CONTINUING TO
MONITOR THIS IN THE COMING DAYS. THEN BY WEDNESDAY...A PATTERN
SHIFTS LOOKS TO BE TAKING PLACE. THE UPPER LOW OVER NORTHEAST
CANADA WILL FINALLY LOSE ITS DOMINANCE AND THE PATTERN WILL TURN
MORE ZONAL...WHICH WILL GENERALLY MEAN WARMER FOR THE LOCAL
FORECAST AREA. ALSO...EVEN WHEN NORTHWEST FLOW ALOFT IS IN
PLACE...THE LOW LEVEL FEATURES ARE INDICATING WESTERLY DOWNSLOPE
FLOW...WHICH WILL ALSO PRODUCE WARMER CONDITIONS. THESE WARMER
CONDITIONS OVER THE SECOND PART OF THE WEEKEND AND INTO NEXT WEEK
WON/T BE SIGNIFICANTLY WARM...MORE LIKELY NEAR NORMAL. ASIDE FROM
SUNDAY...DRY CONDITIONS ARE EXPECTED AS MOISTURE WILL BE VERY
LIMITED DUE TO IT ALL BEING SHUNTED INTO THE DEEP SOUTH BY THE
SYSTEM MOVING THROUGH ON FRIDAY AND SUBSEQUENT WEAK FRONTS PASSING
THROUGH.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1208 AM CDT THU OCT 2 2014

A STRONG UPPER LEVEL DISTURBANCE WILL EXIT WESTERN NEBRASKA
OVERNIGHT. ACTIVITY HAS ALREADY ENDED ACROSS MUCH OF SWRN NEBR
INCLUDING KLBF. SHOWERS AND A FEW THUNDERSTORMS WILL REMAIN
FAIRLY WIDESPREAD EAST OF KVTN...KTIF AND KBBW OVERNIGHT. GUSTY NW
WINDS UP TO 25KT AT KLBF WILL GRADUALLY DIMINISH BY 09Z TO AOB
12KT. ANOTHER DISTURBANCE AND COLD FRONT WILL MOVE INTO NORTH
CENTRAL NEBRASKA DURING THE EVENING THURSDAY...WITH WINDS
34015G25KT P6SM -SHRA FORECAST AT KVTN AFTER 03Z.

&&

.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SYNOPSIS...CLB
SHORT TERM...CLB
LONG TERM...BROOKS
AVIATION...ROBERG








USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.